My 2003 rsx type s idle is higher (1500-2000) while I am coasting in neutral and doesn't change when I push in the clutch but when I come to a stop, the idle drops to normal.
Have you changed your intake manifold lately? It is more than likely a vacuum leak. Also the idle of am RSX stays around 1590-2000 when cold. When it's warm and it does that it's a vacuum leak. IF you don't worry about it for a while and the RPM fluctuates then you know for sure its a vacuum leak.
Well even if I coast for a minute straight the rpm s don't fluctuate like a vacuum leak. They stay steady. Go down when stopped
It can only be 3 things the most common are a dirty throttle body or a small vacuum leak. If it's the small vacuum leak it will eventually start to fluctuate. If the throttle body is dirty it'll stay the same like that until it's cleaned. Either way it's a cheap fix most vacuum leaks are from the intake manifold so you just make sure all the screws are tight. My personal car did it when my screw on the bottom of the manifold was coming loose.
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